Severe Weather In El Salvador

Tornadoes

A tornado forms during severe thunderstorms. The most dangerous of these tornadoes occur from supercells, which rotate thunderstorms with a radar circulation called a mesocyclone. Supercells are characterized by a rotating updraft and are formed in an environment that has a strong vertical wind shear. This wind shear is the change in wind speed and/or direction with height (Tornado Chaser) The formation of tornadoes are believed to occur around the mesocyclone. The VORTEX2 program suggests that when a mesocyclone has formed, tornado development is related to the temperature differences across the edge of downdraft air that wraps around the mesocyclone. (NSLL). 

In the United States, tornadoes can form from any direction. Most of them travel southwest to northeast, or west to east. Tornadoes have been known to change their direction, and even backtrack. In the US there is an average of 1,000 tornadoes recorded every year (NOAA). There are certain locations in the US that tend to have more paths from a certain direction. For example, in Minnesota they usually form from the northwest, and in the coastal areas of Texas they form from the southeast. This happens because of an increased frequency of specific tornado-producing patterns, like hurricanes in south Texas and northwest-flow weather systems in the upper Midwest (NOAA). In El Salvador there have been reported cases of tornado formation, but they are a very rare occurrence. Argentina seems to have the highest rates of tornadoes in South America, as well as the strongest. The strongest tornado in the entire southern hemisphere on record occurred in Argentina on January 10th, 1973. The tornado had winds that were estimated to be equivalent to an F5 intensity (US Tornadoes). 

Global Map of Tornado Activity/Occurrence (US Tornadoes)

Looking at the image above, El Salvador seems to be out of the way of any Tornado hot spots. 

If one were to look at graphs of Tornado occurrences from the last 30 years, it might look like the rates have risen steadily each and every year. However, there are things we must take into account. You could speculate that the reason it seems tornado occurrences have increased is because our ability to detect and monitor them has increased over time, and resources and equipment are now available that were not 30 years ago - Doppler radar for instance. 

Hurricanes

A few things are required in order for a hurricane to form. There must be a sea surface temperature of at least 80 fahrenheit, a vertical temperature in the atmosphere that cools enough with height to support storm activity, enough water vapor in the middle of the troposphere, sufficient distance from the equator for the Coriolis Force to be significant (around 300 miles), and low levels of vertical wind shear. El Salvador has warm waters and a warm surface temperature, is farther than 300 miles from the equator, and usually low levels of vertical wind shear. This might be why El Salvador has been affected in the past by hurricanes. (Hurricane Science). 

In the western North Pacific, hurricanes are referred to as typhoons, and in the Indian Ocean and South Pacific Ocean they are called cyclones. Hurricanes usually form between 5 and 30 degrees North latitude, and typically move towards the west. Looking at the image below, you can see how hurricanes tend to move from the southeast and move upwards in a northwestern direction, but sometimes the winds can be changed in the middle and upper levels of the atmosphere which in turn steers the hurricane towards the north and northwest (NOAA).

Hurricane Formations (NOAA)

El Salvador is rarely hit by any Hurricanes(World Travel Guide), but there are a few occurrences where they were, including Hurricane Mitch in late october of 1998, which killed more than 11,000 people and destroying thousands of homes along the way. It was the deadliest hurricane to hit the Western Hemisphere in more than 200 years (History). From 1982 to 2013, the US received an average of 6.3 hurricanes a year, and 2.4 of those being considered major hurricanes. An average of 1.7 a year hit land, and of those 0.6 are considered major hurricanes (NOAA).